Top 5 Mistakes to Avoid When Installing BoxBolts

BoxBolts make blind steel connections a breeze—no welding, no access to the back side required. But just because they simplify things doesn’t mean you can rush the job. Installation mistakes happen all the time, and they can compromise safety, performance, and your project timeline.

So let’s walk through the five most common errors people make with BoxBolts, and more importantly, how to avoid them.

Table of Contents

• 1. Using the Wrong Hole Size
• 2. Ignoring Torque Specs
• 3. Skipping the BoxSok Tool
• 4. Misjudging the Clamping Range
• 5. Forgetting to Check Edge Distances and Spacing
• Bonus Mistake: Skipping a Final Inspection
• FAQs About BoxBolt Installation

1. Using the Wrong Hole Size

BoxBolts are made for pre-drilled holes. Still, it’s not uncommon for installers to grab whatever bit is on hand and go for it. Bad move.

Hole diameter matters. If the hole is too tight, the expansion mechanism won’t work correctly. If it’s too loose, you end up with a connection that could fail under load.

• Use the drill size specified for your BoxBolt diameter.
• Follow the AISC guidelines for bolt hole tolerances.
• Remove any burrs to ensure proper seating.

Refer to the manufacturer’s spec sheet, found here in the BoxBolt catalog (PDF), or visit the BoxBolt product page.

2. Ignoring Torque Specs

Torque isn’t just a suggestion—it’s critical to performance.

• Under-tighten it? You risk incomplete expansion.
• Over-tighten it? You could deform the bolt or strip threads.

Use a calibrated torque wrench and follow the recommended torque settings from LNA’s documentation. For general guidance, see this torque tightening chart from Engineering Toolbox.

The BoxSok Tool is engineered to:

• Hold the hex head of the sleeve steady
• Allow the core bolt to expand the sleeve effectively
• Speed up installation
• Improve safety by eliminating the need for two wrenches

Check out the BoxSok system here.

4. Misjudging the Clamping Range

BoxBolts come in multiple lengths, each with a specific clamping range. Know your project specs and match them to the bolt.

• Measure total steel thickness
• Match to the correct BoxBolt clamping range
• Use packing pieces if needed

5. Forgetting to Check Edge Distances and Spacing

Installing too close to the edge of a structural tube can lead to failure. Follow AISC guidelines:

• Edge distance = 1.5x bolt diameter
• Spacing between bolts = 3x bolt diameter

Check the BoxBolt design guide or consult an engineer.

Bonus Mistake: Skipping a Final Inspection

Final checks are key. Use a torque audit tool, log values, and take photos. It could save hours of rework. For jobsite safety guidance, refer to OSHA’s steel erection standards.

FAQs About BoxBolt Installation

• What tools do I need to install a BoxBolt?
  At minimum, a torque wrench. The BoxSok tool is recommended.
• Can I install BoxBolts without access to the backside of the steel?
  Yes, they are designed for blind connections.
• How do I know if I’m using the right length BoxBolt?
  Measure the stack-up and check the catalog.
• What should I do if I overtighten a BoxBolt?
  Replace it. Do not reuse.
• Can BoxBolts be reused?
  No. Always use a new BoxBolt for each connection.

Want to avoid every install mistake on your next job?

We offer project-specific kits that include everything you need—pre-measured, pre-matched, and spec-approved. Contact us here to get started.

Last reviewed: June 10, 2025